This chiller in Purchase, N.Y., has an ice-making mode designed to operate during off peak hours in order to provide lower cost cooling the next day during on-peak hours.

Ice storage-based air conditioning systems are gaining renewed interest thanks to incentive-laden projects in the New York City area.

The incentives come from the New York State Energy Research and Development Authority (NYSERDA) that offers “financial and technical assistance initiatives to help with identifying and installing projects which address energy efficiency needs in a way that improves the environment and lessens our dependence on foreign oil,” said Peter Smith, president of NYSERDA. On the receiving end were Morgan Stanley at its corporate office building in Purchase, N.Y., and Credit Suisse at its New York headquarters in Manhattan.

“Aging equipment and the need for additional cooling capacity and site resiliency motivated us to investigate environmentally responsible solutions,” said James McAleer, vice president of facilities for Morgan Stanley. “In addition, the Purchase site will be a beta for similar projects at Morgan Stanley facilities around the globe.”

“Sustainable economic growth and the conservation of natural resources are major priorities of our bank,” said Brady Dougan, CEO of the Investment Banking Division of Credit Suisse. “I am pleased that Credit Suisse’s efforts to conserve energy by acting in an environmentally responsible manner have been recognized by New York.”


Morgan Stanley engaged the Energy Service group of Trane’s New York-New Jersey offices. Trane used the internal technical and financial assistance to propose a thermal solution that would shift the site’s electrical load from day to night. “Energy is more plentiful and less expensive and, in general, more efficient during the night or off-peak hours,” Trane officials said.

The ice storage system provided by Trane makes ice at night during the off-peak hours to provide cooling the next day during on-peak hours. The system is expected to lower the facility’s peak energy usage by 740 kW, reduce overall electric usage by 900,000 kWh and reduce the overall fuel consumption by 15,000 MMBtu.

The system includes a 1,400-ton Earthwise CenTraVac chiller that operates at 0.576 kW/ton in day mode and 0.733 kW/ton in ice-making mode. The ice made by the chiller is stored in 48 Calmac IceBank tanks with a total storage capacity of 8,400 ton-hours. The system has the flexibility to run on chiller only, ice only, or combined operation. There is also an emergency mode that can provide comfort cooling while making ice in the evening. The system includes a crossover plate and frame heat exchanger with added redundancy to the existing data cooling loop and extended the free cooling season.


The Credit Suisse project is expected to lower peak energy usage at the Madison Avenue headquarters by 900 kW, and reduce overall electrical usage by 2.15 million kWh.

Faced with the life cycle replacement of chiller plant equipment, Credit Suisse brought in Trane officials to develop an energy solution that would meet the objectives of energy savings, improved resiliency and environmental consciousness.

One reason for also opting for a thermal storage approach was to reduce consumption and demand with a more efficient low-flow/low-temp chiller water operation and the ability to use the ice system to facilitate the transition between free cooling and mechanical cooling.

The new system configuration consists of three 800-ton Trane CenTraVac chillers and 64 Calmac IceBank thermal storage tanks.

The consulting engineering firm EYP Mission Critical Facilities provided the electrical and mechanical engineers needed to support operations of the facility.

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Publication Date:07/02/2007